I'm sure one of the things the Yanks will look at is their choices of vice captains. They touched on it on commentary that they all play on the Champions Tour so have very little rapport with the players. On the European side all the vice captains and Donald himself have all played with most of the team this year.
Poulter, Westwood and GMac would all have been in the running for captain for the next few Ryder Cups, but have no chance now.
Player power could be a factor, if enough of the senior players want Donald to stay on and can persuade him to do it.